Drug side effect or underlying heart problem?

[Ecin]

Sorry in advance for all of the background information, but I want to make sure you have enough details and I'm not really sure what is relevent or not.  I am 43 years old and have recurring problems with anxiety and hypohtyroidism. A few months ago my doctor prescribed Celexa, but about 4 hours after taking it, I felt dizzy and almost passed out.  A few weeks ago, I had the flu and I was feeling tired for several weeks (my energy levels are starting to increase now). I went to the doctor, he did some blood work, and told me he thought it was post-viral fatigue. I then developed cellutits on my nose which I am taking cloxacillin for- it is resolving. Just after starting the cloxacillin, I started taking Effexor. I took it at about 7:30 pm with dinner and felt fine. At about 2:30 in the morning, I woke up and did not feel well- like I was going to pass out and my whole body was tingling and I was sweating. I thought I was having a panic attack, but when I checked by pulse, it was extremely slow- about 40 beats per minute or less. My heart rate returned to normal in about five minutes and the other symtpoms resovled.Saw my doctor for the lab results- TSH was high, WBC and CRP were high (doctor thinks this is from the cellulitis). My doctor does not think the low heart rate at night is related to Effexor and he wants me to start it again once I am finished the cloxacillin. Since this has never happened to me, I think it could have been caused by Effexor but am also worried it my be an underlying heart problem. I often get a bit lightheaded and sometime dizzy but I've always attributed this to anxiety. I don't get chest pain when I exercise, but I do have a hard time catching my breath when I push myself.

What could have caused such a low heart rate at night?
Could this be an underlying heart problem?
Should I ask my doctor for testing?
Should I get the anxiety under control then ask for heart testing if the symtpoms recur?

[Michael J. McWilliams, M.D.]

1.  It is hard to say without seeing it on a monitor --  it could be premature ventricular contractions, bradycardia, you could have had increased vagal tone, it could be the effexor.  Unless it happens several times, it is unlikely that you will get an exact answer.

2. More of work up would be necessary.  I would start with a Holter monitor.

3. Your doctor will order what they think is appropriate.  you can ask, but it is often difficult to know what to ask for.  If this is the first and only time it has happened, the odds of capturing it again are low.

4.  It is ok to ask about both questions, especially if it is making you anxious.  The problem is the honest answer is probably that your doctor doesn't know what caused it and it would need to be a recurrent problem to give your doctor a chance to figure it out.  Never be afraid to ask a question to your doctor.  Sometimes we don't know the answer.

[heart_of_mine]

Both Celexa and Effexor are drugs known to cause QT prolongation. QT prolongation can lead to ventricular arrhythmias causing fainting, seizure-like activity and sudden cardiac death. Hypothyroidism is also known to cause QT prolongation. I would probably seek a second opinion on this and get an ECG done to make sure that you don't have a prolonged QT interval. More rarely, QT prolongation from medications can unmask an underlying genetic condition called Long QT Syndrome which needs to be treated. This is something that is commonly overlooked by most doctors. Trust me!

[kizzie100]

Is there a possibilty that anti-convulsants cause QT prolongation? My daughter aged 21 recently died in a nightclub.  Her death has been attributed to Long QT syndrome.  She had been diagnosed as having epillepsy in her teens. The specialists say Chloe may never had had epilepsy.  It was decided that our son should have tests too.  During pre-assessment for an EP study Alex had a vaso-vagal reaction when taking blood and his heart stopped momentarily.  He had another episode in hospital again vaso-vagal and his heart stopped again.  He was subsequently fitted with an ICD (he is only 19 years old!).  As a teenager I was also diagnosed with epilepsy but again the consultants feel this was most likely a misdiagnosis.  The EP consultant feels i too should have an ICD fitted as i had an unexplained cardiac arrest 7 years ago and survived!!! i have just had some genetic testing done.  I dont feel i have much of a choice really.  But i do wonder if anti-convulsants may have caused a prolongation on the QT interval also?  

[stevie_wonder]

Hi,
I'm so sorry to hear about your daughter. It's good that your son has ICD protection now. You should probably get one too with your history.
The doctor usually only answers the first persons question in each thread so I will try to help you. Many people get misdiagnosed with Epilepsy when they in fact have LQTS and were prescribed anti-convulsants. I don't think they are on the QT Drug List. You can check out the drug list at www.qtdrugs.org and see if the medication is on the list.
Genetic testing can only give answers in about 70% of the cases, hopefully this is true for your family.
Take care